Screen door latch



June 11, 19 57 A. ERKK|LA 2,795,446

SCREEN DOOR LATCH Filed Aug. 26, 1953 2 Shets-Sheet 1 s5 INVENTOR.

- .flndrewzrkk'ila BY a ATTORNEY June-11, 1 9574 ERKK|LA 2,795,446

SCREEN DOOR LATCH Filed Aug. 26, 1953 2 Sheets-Sheei 2 VII/11101111191; 48

INVENTOR.

M Kim I ATTORNEY Unitd States Patent SCREEN DOOR LATCH Andrew Erkkila, Fitchburg, Mass., assignor to Independent Lock Company, Fitchburg, Mass., a corporation of Massachusetts Application August 26, 1953, Serial No. 376,675

7 Claims. (Cl. 292-169) This invention relates to screen door latch sets and more particularly to latch sets having a short backset and means of mounting the same.

This invention is a continuation-in-part of my application Serial No. 338,077, filed February 20, 1953, now Patent No. 2,770,481 of November 13, 1956.

My invention more specifically concerns itself with the problem of installing a latch set on door frames, such as screen doors or, as more recently introduced, screen doors and storm doors made of aluminum frames in which the hollow stiles thereof are of narrow dimensions, to hold replaceable screens or glass lights serving as insulation barriers to form storm doors.

I As in the invention of my prior aforesaid application, efforts by me to embody in a frame for a door of the character described a simple spindle actuated latch 'bolt have encountered dimensional problems in endeavoring to retain the proper operating conditions.

Prior to my invention aforesaid, due to the extremely short backset, the incorporation of a spring to project the latch bolt, of requisite stiffness to orient a lever handle against sagging, while afiording independent yieldability to the latch, and assuring long life of the movable parts, had not been found successful.

Accordingly, it is an object of my invention to provide a latch assembly or door set for narrow stiles involving short backsets of the spindle in which adequate spring compressibility for spindle and knob orientation is combined with soft nose resilient yieldability for independent latch bolt depression, and particularly in which the assembly eliminates the need for any special tools in afiixing the latch set in position by eliminating any hand operation, thereby providing completely factory assembled parts free from access for tampering.

Still more particularly it is an object of this invention to provide a screen door lock set having a spring projected latch bolt actuated by double compression springs combining to have the requisite stiffness to orient the spindle to a normal position and project the latch bolt for effective strike-socket engagement, but also to include a soft spring reaction to independent depression of the latch bolt, as when the latch bolt is cammed by the strike plate and to combine these features in a casing which holds the relatively movable parts together by metal stamping operations, eliminating the tedious work of hand assembly by screws in both setting the mechanism or afiixing the latch in position, and thereby effecting substantial economies in manufacture and labor.

To attain these objects and such further objects as may appear herein or be hereinafter pointed out, I make ref erence to the accompanying drawing, forming a part hereof, in which- Figure l is a sectional view of a latch set in accordance with my invention, mounted on a metal stile door;

Figure 2 is a section taken on the line 2-2 of Figure l; Figure 3 is a fragmentary section taken on the line 33 of Figure 2;

' Figure 4 is a magnified section along the line 4-4 of Figure 2;

Figure 5 is a section taken on the line 5-5 of Figure 4; Figure 6 is a section, partly in plan, similar to Figure 5 with the latch bolt in the depressed position in engagement with the camming portion of the strike plate;

Figure 7 is a view similar to Figure 6 showing the latch bolt retracted by spindle knob action;

Figure 8 is a section taken on the line 8--8 of Figure 5; Figure 9 is a section taken on the line 9-9 of Figure 7. Making reference to the drawing, I have illustrated my invention in connection with a metal door 10, a fragment of which is shown, having a tubular stile 11. Such frames may be of sheet metal and preferably extruded aluminum, serving the double purpose of both a storm door during the winter and a screen door during the summer. The stile 11 has a closure edge 12 provided with a channel 13 into which there is seated the flange 14 extended from the latch casing 15. The latch casing is tubularly formed and has a bottom, integrally connected wall, shown as the closed end wall 16, and an open end 17 adjacent the supporting end flange 14.

The latch mechanism is assembled into the casing 15 through the opening 17 and for this purpose there is first introduced into the casing a coiled compression spring 18 which is axially restrained and guided on the'protrusion 19.

With this construction there is separately provided ,a cam frame. 20 comprising branches 21, 22, extending from the seat 23. The seat 23 generally is contoured to slide within the casing 15 and is formed with a passage 24 to receive the spring 18 therethrough.

Slidably mounted between the branches 21 and 22 there 9 is positioned the cam follower block 25. The cam follower block 25 has a base flange 26 formed with slots 27, 27, into which the branches 21 and 22 extend, the cam thereby being held slidably against rotation. The cam is formed at its rear end with a boring 28 into which the coiled spring 18 may extend in seated position.

Thereupon there is positioned between the branches 21 and 22, the generally circular spring plate disk 29, having an axial spring centering protrusion 30 and peripherally formed with guide slots 31-, 31 to clear or receive the branches 21, 22 for slidable guiding movement in respect thereto, or for clearance.

The free ends 32 and 33 of the branches 21 and 22 are headed to form locking shoulders 34 for engaging the latch bolt 35 in slots 36 formed therein, the walls 37 of the slots being peened-over to engage the shoulders 34 and hold the latch bolt 35 and cam frame 20 in assembled relation.

With this assembly thus affected, there is positioned in tandem relation to the first spring 18, an expansion spring 38 which is axially held by the protrusion 30 of the plate 29 at one end and which projects into a spring seat 39 in the latch bolt at the other end. I

With the cam frame, cam, spring plate and latch thus the plurality of seats 40 which are peripherally staggered.

to permit clearance of the branches 21 and 22, yet serve to engage the periphery of the spring plate 29 and act as stops for inward projection of the spring plate. When the spring plate has been seated upon the indented seats 40, the spring plate is locked against displacement outwardly by the indentations 41 through the casing against the forward portion of the spring plate 29.

With this construction, the latch bolt assembly is intact as a complete unit which may not be altered after assembling, without cutting away, ironing out or otherwise flattening the indentations 41, the latch bolt 35;being-depressible to the limits of the spring plate 29, there being clearance slots 42 to pass the indentations '41, 41.

The casing is formed withdiarnetrically positioned cutout slots 43to-receive the latch case support rod 44,: as will appear more clearly as this description proceeds.

With'the unit completed as described, the. casing, may now be assembled with the door stile 45, the edge of which. is formed with a channel 46 through which an end boring 47 is formed to receive the latch casing 15 and position-the flange 14 between the webs 48. The outer face wall 49 and inner face wall 50 of the stile are formed with slots 51 and 52, respectively. These slots are positioned to be in alignment with the slots 43 of the casing.to'receive the casing support 44 through the four apertures. Initially, the casing-support is flat to projectone of the ends 53-and54 into threading position. Thereafter the ends 53 and- 54 are bent at right angles against either of the faces 49 and 50 of the stile, to lock the casing 15 against displacement on the frame. In the position described, the spindle apertures 55, 55 of the casing and 56, 56 of the stile are brought into alignment, whereupon'the outside escutcheon'57 and inside escutcheon 58 are fixed to the stile by the screws 59, 59 and 60, 60. The outside escutcheon 57 carries a spindle lock 61, slidable to and from the spindle by the button 62 along the guide slot 63. The lock 61 consists of a keyhole type slot 64 to engage the spindle in the upwardly projected position but permitting the spindle to rotate to the downward position shown in Figure 2.

With the parts as thus assembled, the outside knob 65 with its spindle-rock shaft 66 is projected through the alignment stile apertures 56, 56 and enter the casing'apertures 55, 55. The forward end of the spindle is provided with a sharpened nose 67 to depress the cam follower block 25 against the spring pressure of the spring 18 until the retractor portion 68 of the spindle-rock shaft is seated upon the nose 69 of the cam follower block 25. In this position, the lever handle 70 is coupled with the spindle66 and locked by the set screw 71 in the desired position, the spindle being thus trunnioned by the usual bearings of the rose and knob and lever handle shanks. The retractor portion 68 of the spindle-rock shaftacts as a stop to restrain the cam frame from outward projection.

With the assembly thus completed, the door frame 72 is morticed or otherwise formed with a cutout to receive the strike 73, having the strike plate cam 74 in the position to depress the latch bolt 35.

With this installation it will be observed that when the door is independently swung to the closed position to abut the stop 75, the latch bolt will be cammed by the strike plate cam 74, to actuate the latch bolt and the cam frame carried thereby against the single spring tension of the spring 38, as shown in Figure 6, to give a soft resilient resistance as the door moves to the closed position. Thereupon, as will be readily understood, the latch bolt 35 passes the plate to enter the strike aperture 76, the latch bolt thereupon being projected or biased under the influence of the spring 38 and the cam follower block 25 being biased under the influence of the spring 18, this latter spring pressure being exerted to drive the nose 69 in the retractor seat 68a, orienting the lever handle 70 by reason of the spring pressure in a normally horizontal position.

To withdraw the latch bolt by turning the knob 65 or the lever 70, the retractor 68 is moved rockingly as shown in Figure 7 to the position where the retractor bears against the cam to draw the latch bolt in the retracted position against the spring pressure of the springs 18 and 38, thereby giving a double spring tension against the resistance of a turning movement and double spring projecting: influence in orienting the cam follower block 25. since the spring 38, in projecting the latch bolt 35 through" the influence of the'straps 21' and 22, and the 4; slot 23, presses against the cam follower block 25 by a pulling force.

The earn follower block 25, under any circumstances, floats, so-to-speak, upon independent depression of the latch bolt as when it strikes the strike plate cam 74, leaving the nose 69 to exert its spring projected pressure upon the retractor 68 in the properly oriented position, whereupon no further action. is necessary to align the spindle with the narrow slot portion 64 of the locking mechanism when it is desired to move it to engage the squared spindle for locking the spindle against rotation.

It will be observed that while I have shown and described the completionof the latch assembly by means of the indentation 41 integrally formed in the casing upon completing the assembly, it will be understood that this aihxing means may comprise removable elements, such as by the projection of removable pins or screws. Alternatively, the locking elements 41. may be omitted entirely-to await the installation of the casingand the associated parts in position on the door. Thus, I may either per.- manently or removably assemble the casing, the latch bolt frame and cam follower block in the latter alternative, relying in partupon the support rod 44 to prevent the spring 18 from projecting the latch bolt assembly entirely from the casing until the rock shaft spindle is placed in finalposition to serve a similar purpose as the indentation or until after the rock shaft has been removed for any purpose, as when it may be desirable to replace the springs or other worn parts or for purposes of changing the hand of the door.

Likewise it will be observed that the support rod 44 may, in part, serve to key together several parts of the latch to permit omission of the spring plate 29 and the indentations 41. This assembly will still retain a desirably operative latch,.even though removal may be effected at the time that the latch is mounted on the door stile.

Likewise, the support rod 44 may be attached to the casing 15 and other means used to support the casing in the boring. as when the latch bolt is mounted on a wooden door, in which case the walls of the boring support the casingin position.

It will be observed from the installation which I have described that all of the features of my prior invention are secured inproviding a latch bolt casing having a very narrow backset, yet securing all of the desirable advantages of a-soft-nose spring. projection where the latch bolt is independently depressed and having adequate rigid spring projection under the influence of both springs for orienting the spindle to provide a non-sagging lever hand-le and a floating cam follower to facilitate installation of the casing. in the door frame. The springs are-positioned in a very compact assembly, permitting complete clinching of the parts at the factory, free from any tam-- pering influence, the'axial orientation of the springs assuring long life and freedom from any jamming influence, should the latch bolt or latch bolt frame be depressed to the limits of capacity of the casing.

While I have described my invention as applicable to the screen doors and storm doors in accordance with my invention as made in hollow stiles, in using aluminum, and particularly have shown a door stile 45 formed with a channel 46 having webs 48, it will be understood that the doors could be made of stainless steel or ordinary steel if adequately plated or protected against the weather by painting. It will also be understood that the door edge in the latter described construction may not be fitted with the channel and the flange 14 of the casing 15 may be fitted to be flush with the edge 12 by counterboring the same.

It will be observed, in general, that I provide. a highly eflicient and economical assembly while" retaining the desirably small dimensions, permitting installation in an extremely narrow frame, particularly screen or storm door frames of aluminum or like metal.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is:

1. A latch of the character described having an integral latch bolt casing and a spring projected latch bolt, the combination comprising a cam frame slidably guided within and by the side walls of said casing to which said bolt is directly connected, a floating cam follower block guide slidable on said frame for actuating the cam frame to retract or release the same, independent spring projecting means for said latch bolt and follower arranged in tandem, a rock shaft arranged to extend through said casing to actuate said cam follower block against both of the said springs in unison to retract the latch bolt, said cam frame being yieldingly depressible against one of said springs and slidably guided in relation to said follower to leave the other spring to hold said rock shaft in predetermined position by engagement with said follower.

2. In a latch of the character described including a tubular latch bolt casing having a closed end and an open end, and a spring projected latch bolt extending through said open end, the combination comprising a cam frame including a looped strap having branches to each side of a guide disk, means to hold said disk relatively fixed in said casing, said branches having their free ends extending into engagement with said bolt, a cam follower block mounted to engage the frame in retraction of said latch bolt in the compressed position of said latch bolt, slidably guided between said branches in relation thereto and spring biased independently of said disk, a rock shaft arranged to extend through said casing for actuating said cam block follower, and a second spring arranged in tandem with respect to 'said first spn'ng, engaging said bolt to bias the same with relation to said disk and project said bolt and engage said follower with said rock shaft.

3. A latch in accordance with claim 1 wherein said spring for said latch bolt is biased against a spring plate guide for said frame and includes protrusions in said casing to hold said spring plate.

4. A latch in accordance with claim 1 wherein said spring for said latch bolt is biased against a spring plate guide for same frame and includes protrusions in said casing to hold said spring plate, and indentations to hold said plate against displacement.

5. In a door of the character described having a tubular stile, a latch in accordance with claim 1 having a casing support extending through said door frame and casing comprising a deformable strip and escutcheons overlying said strip.

6. In a door having a tubular stile and an end channel, the combination therewith of a latch casing having a flange portion seated in said channel and extending into the tubular stile independently of the same and providing a support for one end of the casing, a casing supporting member extending through said stile and casing, having the ends bent over said stile in engaging position, providing a support spaced from the flange end portion in opposed relation to said channel.

7. A latch of the character described including a tubular latch bolt casing having a closed end and an open end, and a spring projected latch bolt extending through the open end and guided by the side walls of said casing, the combination comprising a cam frame slidably guided by and within said casing including a looped strap having branches, a cam follower independently slidable on said branches, spring projecting means for said cam follower, spring projecting means for said latch bolt, a spring plate for said latter spring projecting means, stop means for said spring plate on one side thereof and indentations as the means for holding said spring plate whereby said cam plate and latch bolt are held within said casing under the combined biasing influence of said springs.

References Cited in the file of this patent UNITED STATES PATENTS 1,560,897 Dexter Nov. 10, 1925 1,871,633 Ter Meer Aug. 16, 1932 2,231,443 Gerard et al. Feb. 11, 1941 2,238,314 Falk Apr. 15, 1941 2,302,380 Schlage Nov. 17, 1942 2,369,874 Voight Feb. 20, 1945 2,413,733 Schlage Jan. 7, 1947 2,479,174 Lickteig Aug. 16, 1949 2,634,151 Russell et al. Apr. 7, 1953 

